#22

definitely recommend cranks stuff, especially the vocal mics ($10!)

here’s a modern classic preamp design
http://www.zachpoff.com/diy-resources/alex-rice-piezo-preamplifier/

3 Likes
#23

A couple quick fun things,

I know Peter Blasser uses piezos as control input on the Shnth, and I’m assuming a few other instruments - I have no idea personally how it’s done, but I imagine a softer piezo on a flexible-ish surface could be used for very expressive CV control. Don’t flex it too much though, or it will snap :slight_smile:

And then check out Tom Nunn’s work - a buddy of mine has one of his handmade instruments, which is basically a bunch of brass rods cut to different lengths and hammered into a resonating board with a contact mic on it, and you play it with combs! Pretty cool.

1 Like
#24

Does anyone have any info on non-peizo based contact mics?

#25

how about… http://leafcutterjohn.com/?p=1518

EDIT: actually I guess these are piezo contact mics, but not the usual gold coins we’re used to…

#26

In his instruments its super simple, it’s literally just a piezo connected as a CV source!
(probably with some clipping/limiting inside the standalone instruments), but a piezo will produce a positive (and negative) voltage passively, so you don’t need a lot to get going. The only thing is that it can produce a pretty big spike as well, hence the potential limiting.

Unless I’m mistaken, I think the barre controller is literally 4 piezos connected to four jacks, and that’s it.

I’ve played with film piezos a bit, both as a contact mic, and as a CV source (controlling Blasser synths). The output level from them is waaaaaay lower than a piezo disc, so you’ll a preamp/buffer for sure.

If you’re looking for info on different types of contact mics, I re-recommend this book:

2 Likes
#27

yes,This is one of the Bart Hopkin books - great stuff. in it he discusses a potential slack coil type contact pick up but i have not made one. Just wondered if anyone has seen/used products like this out there . or also wondering if their are other alternatives to the peizo crystal.??

#28

Yes, Johns contacts look good - nice looking things. Also love to have a go at the grow-your-own-crystal some day too.

#29

aha! Just thinking about this question again I remembered another twist on the theme (not strictly speaking a contact mic) - the bass pickup stompbox:


I was gonna build one of these, picked up a bass pickup very cheap but realised the BC license plates of my now-defunct crappy car are aluminium - d’oh!

Anyway a lightbulb just went off, realised it’s another use for 19" rack blank… Nice how everything comes together (sometimes)

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#30

Has anybody experience with these mics here: https://hydrophones.blogspot.it/

#31

Yes, pretty good for the money. The contact mics produce good levels of high frequency content, something a lot of others at that price bracket lack.

Here is a sound from the hydrophones (with significant Hi boost, if I remember)

#32

I’m happy with my mics that Jez built. I plan on ordering another hydrophone and contact mic before another trip out west so I can tinker with stereo stuff. I’m going alone so I should have more time and quietude for field recording :slight_smile:

#33

have to agree with that - if you are going field recording go alone.:microphone:

#34

I seconds everyone that has mentioned that as decent preamp is key if you want accurate representation of sound…I’ve also made the mint box preamp Rodrigo mentioned, it works well in my experience for capturing low pitched objects, but didn’t sound great for things like a snare drum.
The Alex rice preamp design is fantastic, and a small 2 person company in Chicago is now manufacturing kits - http://zeppelindesignlabs.com/product/cortado-balanced-piezo-contact-mic/

The kits are super easy…I made one of these on perforated and the compact size of the ZD model and already matched JFETs are well worth 25 dollars in my mind. It DOES require phantom power. ZD also sells a DIY phantom power supply that runs off a 9v and works really well. You can go ultra dork like me and put them all into one tidy box. This system works well for me since I can make numerous different sizes and shapes, and lengths of contact miss and run them through one preamp. The altoids box contains the PP and the circuit wrapped in copper tape is the preamp. Good luck!

image.jpeg1936×2592 1.47 MB

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#35

I have some contact mics I’ve made myself and coated in plastic-dip. When I record them into my field recorder, I find using an impedance transformer improves the bottom end considerable (my Tascam doesn’t have a hi-z input). I use a HOSA MIT-129 http://hosatech.com/product/mit-129/

#36

16 posts were split to a new topic: Transducers / Exciter Speaker

#37

I’ve been looking into ears recently and after seeing this video https://youtu.be/Bv6nDi7i-S8?t=667 it convinced me that I need a contact mic. I have a drumkit and when he runs the cymbals through his modular it just sounds too cool.

#39

I use a Radial Engineering PZ-DI for the same reason, I couldn’t believe it first time I plugged my DIY piezo in it, it’s night and day with and without it. http://www.radialeng.com/pzdi.php

They even include a variable high-pass filter for removing the excess of bottom end you’re finding back when matching impedance (it’s really useful), plus the load is variable with a 3 position switch (electromagnetic/standart/piezo), there’s a pad, an LPF and you can lift the ground.

The only downsides is that it needs +48V and it’s pricey at 220€, I know they also make a simpler, cheaper, version (SB-4), but I’m gonna try your solution for when I need to record various piezo at the same time (can’t afford multiple PZ-DIs right now…)

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#44

If I have a stereo 1/8 mic/line input (sony pcm-m10), would it be worth it to buy this with a xlr to 1/8 cable adapter?

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#45

So you’d be plugging the impedance transformer into the xlr to mini jack adapter and then into your recorder? I think that should work, but it will be rather bulky and you may get a little signal loss from the adapters. It’s not something I’ve tried myself

1 Like
#46

yes, that’s what I was hoping to do but maybe you’re right that it would be an overly complicated setup. JrF says that his microphones don’t need a preamp so I’ll try those but I wanted to extend the frequency range on my cheaper contact mics as well